The present invention relates to a static dissipator for dispersing to the atmosphere the static buildup of electric charge on a structure in order to prevent lightning strikes. More particularly, this invention is directed toward a static dissipator having an electrically conductive core with wire filaments extending therefrom which terminate in fine dissipation points and with the core and wire filaments enclosed in a plastic housing.
Lightning is caused by electricity passing through the air. More specifically, the rapid movement of air causes varying concentrations of charges to be created on the water particles located in a cloud. As a general rule, the central portions of the cloud have positively charged ions while the lower portions of the cloud have negatively charged ions. The rain droplets that fall to the ground carry positive charges to the earth's surface. A lightning strike occurs when the negatively charged portion of the cloud seeks to neutralize itself with the positively charged earth.
It is known that lightning always seeks the path of least resistance on its descent to the earth's surface. Unfortunately, trees, houses, towers, watercrafts and other structures are usually the objects that provide lightning with an easier or least resistant path. Accordingly, lightning often strikes such objects thereby causing severe damage and destruction.
Lightning rods have been used for many years to reduce the damage caused by lightning. The conventional lightning rod is electrically grounded and is attached to the structure to be protected. Accordingly, the lightning is attracted to the rod and the charge is directed directly to ground thereby preventing structural damage. However, even if the structure is properly grounded, the lightning rod brings approximately 12,000 to 20,000 amps at 100,000 volts within a few feet from sensitive equipment such as phone lines, electrical service lines and cable TV lines. Surges created by the lightning can overload the circuits thereby damaging this sensitive equipment.
In order to alleviate the potential damage to electronic equipment, lightning dissipators have been developed that disperse electric charge on an object into the atmosphere so that the likelihood of lightning strikes is reduced. For example, U.S. Pat. No. 4,605,814 discloses a lightning deterrent device having a brush-like conductive structure that is particularly suited to be mounted on the top of a transmission tower. The device includes a cable formed in an annular configuration with a plurality of wires extending therefrom. The dissipator is adapted to be mounted around the periphery of a transmission tower and has a diameter that is sufficient to contain the vertical sides of the structure to be protected. Accordingly, if this device were to be used to protect a very large building, it would necessarily have a large diameter in order to contain the building's vertical sides. This can be rather impractical.
U.S. Pat. No. 4,910,636 discloses a static electricity dissipator having a plurality of conductive wires fitted through an opening in the upper portion of a tubular base member. The base member must be crimped in order to secure the wires thereto. The number of wires, and therefore the number of dissipation points, is limited by the diameter of the opening since the proximate ends of the wires are positioned therein. Accordingly, this dissipator does not sufficiently dissipate electric charge into the atmosphere.
Patent Nos. D 308,175 and D 339,306 describe more compact dissipators. However, they are not so aesthetically pleasing that one would want to utilize the same on a watercraft where it would be in plain view. Furthermore, because the wires are exposed in these prior devices, injuries could be sustained by persons who may contact the same.